软岩隧道中双层初期支护的应力情况分析

Stress Analysis for Double Preliminary Support in Soft-rock Tunnel

摘要:

两水隧道穿越的地层主要岩性为炭质千枚岩，地质情况较差，围岩破碎度高，节理发育。自2009年两水隧道开工建设以来，隧道工程问题层出不穷，出现了初期支护开裂、破坏，甚至出现二衬开裂、掉块，仰拱隆起等严重的隧道结构破坏现象，施工进度缓慢。在进口桩号为DK359+712～ DK359+742段采用双层初期支护和单层二次衬砌的支护方式，取得了良好的效果。通过应力情况分析为炭质千枚岩隧道的支护选型提供了依据。

Abstract:

The main lithology of the strata that Liangshui tunnel crossed is carbonaceous phyllite with poor geological conditions, the surrounding rocks are broken with high breaking degree and joint development. Since the construction of Liangshui tunnel in 2009, the problems of tunnel engineering have come out in an endless stream. The preliminary support cracking and failures happened, even serious tunnel structure failure such as cracking of the secondary lining, block falling and inveted arch uplift occurred, which led to slow construction progress. In the section of imported pile number of DK359+712～ DK359+742, good results have been received by double-layer preliminary support and single-layer secondary lining. The analysis on the stress situation provides a basis for the support mode selection of carbonaceous phyllite tunnel.